Steel Confinement Boxes SCB

Zone 1 - Innermost confinement zone, consisting of the 11 steel confinement boxes (SCBs) and associated ventilation ducting. 

Portions of the HCF structure, along with the steel confinement boxes (SCBs), gloveboxes, fume hoods, and the ventilation systems perform confinement functions. These confinement systems provide defense in depth by ensuring that hazardous materials are retained in specific designated areas within the HCF. They accomplish this function by maintaining an air pressure differential hierarchy from regions of greater contamination to those of lesser contamination within the facility. These differentials are described later in this section. This pressure differential controls the movement of contamination by diffusion and by adverse airflows. The Identified contamination zones in the HCF are as follows ... 

Processing Steel Confinement Boxes (SCB) Safety Function... 

HCF personnel, ES H Center personnel, and Facilities Operations and Engineering (FOE) Center personnel share responsibilities for initial startup testing at the HCF. For example, HCF personnel may functionally test tools and equipment intended for use in the steel confinement boxes (SCBs) using the mockup manipulator arm located in Room 101 before the tools and equipment are inserted into the SCBs. ES H Center personnel test the radiation-monitoring system. Facilities Operations and Engineering Center personnel are responsible for performing initial tests on all major modifications, and SSCs under their jurisdiction (e. g., fire-suppression system). 

Zone 1 consists of the Steel Confinement Boxes (SCBs) located within Zone 2A (hot cell canyon).- The SCBs are considered to be a normally contaminated area and is classified as an H7 occupancy. The SCBs are constructed of stainless steel and will contain low volumes of combustible materials and process chemicals. The combustibles primarily consist of small amounts of plastics and charcoal filter media. The plastics consist principally of syringes and bottles needed for the extraction of the Isotopes. The ignition sources within the SCBs are electrical outlets and target heaters. 

Contamination Process fission products and actinides -Overpressure in steel confinement box (SCB) -External event -Breached container Liquid nitrogen for cooling in SCBs may leak or otherwise evolve N2 gas forcing out the manipulator boots. 

Steel confinement boxes (located inside the Zone 2A canyon) serve as passive defense in depth barriers to the potential uncontrolled movement of radioactive materials from isotope processing activities under normal and abnormal conditions. These SCBs serve no other functions that meet safety-related criteria. 

All operations with loose radioactive materials occur in sealed confinement structures, such as the Room 113 gloveboxes, the SCBs, the Steel Transfer Box (STB), or under the Room 113A fumehood. These confinement structures are well ventilated and the exhaust filtered through the HCF "hot" exhaust system. (See Chapter 2, "Facility Description," for a discussion of these and other facility design features that limit the spread of contamination.)... 

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